1. Field of the Invention
Aspects of the present invention relate to a method of fabricating an organic light emitting diode (OLED) display device, and more particularly, to a method of fabricating an OLED display device in which an organic layer is formed by transferring a transfer layer.
2. Description of the Related Art
Generally, an OLED display device is fabricated by forming an anode on an insulating substrate, forming an organic layer on the anode, and forming a cathode on the organic layer. The organic layer includes an emitting layer, and may further include at least one of a hole transport layer, a hole injection layer, an electron transport layer, a hole blocking layer, and an electron injection layer.
To form the organic layer, deposition, inkjet printing, or laser induced thermal imaging (LITI) can be used. LITI is a method of forming an R, G, or B organic layer by irradiating a donor film including a light-to-heat conversion layer and a transfer layer formed on the light-to-heat conversion layer with a laser beam such that laser energy is converted into thermal energy by the light-to-heat conversion layer and the transfer layer is transferred to an acceptor substrate by the converted thermal energy. The donor film may be irradiated with the laser beam selectively, such that the transfer layer is transferred to the acceptor substrate only at predetermined locations. During the formation of the organic layer through LITI, the donor film is adhered to the acceptor substrate, but after the transfer layer is transferred to the acceptor substrate, the donor film and the acceptor substrate are separated from each other, leaving behind the transfer layer adhered to the acceptor substrate. To facilitate the transfer process, tensile force may be applied to the donor film using clamps disposed at opposite sides thereof.
The separation of the donor film from the acceptor substrate may be performed by injecting air between the donor film and the acceptor substrate to urge the donor film apart from the acceptor substrate. If the separation of the donor film from the acceptor substrate is not carried out smoothly, lifting of the transferred transfer layer from the acceptor substrate may occur due to adhesion between the transfer layer and the donor film and due to the tensile force applied to the donor film. In particular, if the tensile force applied to the donor film is applied in a direction perpendicular to the long side of a pixel opening (for example, in the direction B shown in FIG. 1), the long side of the pixel opening is under a lot of stress due to the tensile force, and thus, there is a relatively large region of the pixel opening where it is possible to have lifting of the transfer substrate from the acceptor substrate when the donor film is separated from the acceptor substrate.